Brawworks



April 16, 1935. E. E. GREVE 1,993,013

DRAWWORKS Filed March 17, 1931 5 Sheets-Sheet 1 E. E. GREVE April 16, 1935.

DRAWWORKS Filed March 17, 1951 3 Sheets-Sheet 2 jNVENTOR I F W BJMW E. E. GREVE DRAWWORKS April 16, 1935.

Filed March 17, 1931 5 SheetsSheet 3 Patented Apr. 16, 1935 UNITED STATES PATENT OFFICE DRAWWORKS Application March 1'7,

5 Claims.

This invention relates to a drawworks which is provided with a power take-off. More particularly, this invention relates to drawworks which are to be used in oil well drilling.

The power requirements for drilling an oil well are met, for the most part, if driving means are provided for the slush pump, the hoist or drawworks, and the rotary table. It is customary to provide a common prime mover for driving both the drawworks and. the rotary table. The rotary table is generally driven through a sprocket mounted on a shaft arranged parallel with the drum shaft of the drawworks. It is not convenient, as arule, to drive directly from the prime mover for the drawworks to this driving sprocket of the rotary table. Accordingly, various arrangements have been suggested for driving this sprocket of the rotary table from various shafts of the drawworks.

It is one object of my invention to provide means for driving a rotary table from a shaft of the drawworks and to provide in the driving means an arrangement for changing the speed at which the table is rotated. A further object of my invention is to drive the rotary table from a shaft which is close enough to the driving sprocket of the rotary table so that sagging of the drive chain is not a problem. Further objects of my invention will become apparent in the course of the ensuing description.

In the drawings in which for purposes of i1- lustration and not as limiting my invention, I have shown an embodiment which the same may assume,

Fig. 1 is a front view in elevation of a drawworks provided with a power take-off for driving the rotary table;

Fig. 2 is a plan view of the drawworks; and

Fig. 3 is a rear view in elevation of the drawworks.

The drawworks shown in the drawings is, for the most part, supported by a frame comprising two posts 2, 2. A drum shaft. 3 is rotatably supported in bearings mounted on the posts 2, 2. A counter-shaft 4 is rotatably mounted parallel to the drum shaft in bearings carried by the braces 5, 5 of the frame. It will be noted that the shafts 3 and 4 are at substantially the same level.

A line shaft 6 is rotatably supported in bearings carried by the posts 2, 2, this shaft being at a higher elevation than the two previously mentioned shafts. Clutches 8, 8 are provided on the counter-shaft for controlling driving of the hoist drum. One of these clutches controls a sprocket 9 and the other controls a sprocket l9, these sprockets being rotatably mounted on the counter-shaft 4. The sprocket 9 drives a sprocket H secured to the line shaft 6, and the sprocket it) drives a sprocket l2 likewise secured to the line shaft 6. The drum may be driven through 1931, Serial No. 523,235

either of two sprockets on the drum shaft, and rotatable thereon. The sprocket [4 on the drum shaft is driven from a sprocket I8 keyed on the line shaft and may be connected to drive the drum shaft 3 by means of a clutch l6; and a sprocket IS on the drum shaft is driven from a sprocket l9 keyed on the line shaft and may be connected to drive the drum shaft 3 "by means of a clutch H.

The counter-shaft 4 has secured thereto a small sprocket 20 through which it may be driven from the prime mover at one speed, and a larger sprocket 2| through which it may be driven from the prime mover at a slower speed. It is apparent, therefore, that provision is made for driving the counter-shaft 4 at either of two speeds and for drivingthe line shaft 6 at any one of four speeds. Moreover, there is a further choice of speeds between the line shaft 6 and the drum shaft 3, as the operator may select either the clutch IE or the clutch II. It .is apparent, therefore, that the drum shaft may be driven at any one of a pluralityof speeds.

The end of the countereshaft 4 extends past the brace 5 on the opposite side of the drawworks from the operators position. on this extended end is rotatably mounted a sprocket 23 which may be connected to the counter-shaft 4 by a clutch 24.

I have provided means for establishing a driving connection between the counter-shaft 4 and a rotary table. Such a rotary table is customarily provided with a sprocket mounted on a shaft parallel with the shafts 3 and 4 of the drawworks. The driving connections which I provide between the counter-shaft and the rotary table comprise speed reduction means. These speed reduction means are in the illustrative embodiments shown in the drawings carried by the drawworks; and for purposes of convenience, I have shown the speed reduction means mounted on a continuation of the drum shaft 3. The speed reduction means are not driven by the drum shaft 3, and the construction would be no different in principle if a separate stub shaft were caused to project from the side of the drawworks so as to support the speed reduction means. In the form shown in the, accompanying drawings, a sprocket 25 is rotatably mounted on the projecting end of the drum shaft 3. A sleeve 26 is formed integral with the sprocket 25, it being obvious that the sprocket 25 might be made separate and secured to the sleeve 26.

adapted to intermesh with the jaws 32. Mechanism 35 comprising a ring 36, a yoke 31 and a screw 38 is provided for moving the gear 21 longitudinally of the sleeve 26. A shipper member 39 cooperates with a nut 40 on the screw 38 so that the operator may move the screw 38 longitudinally to shift the gear 21. i The nut 40 is provided with a hand wheel 4| for adjusting the nut 40 longitudinally of the screw 38. Mechanism, not shown, is provided whereby the operator may shift the shipper member 39 to shift the gear 21. w

A frame 43 is secured to the post 2 and carlies a ring gear 44. A plurality of studs 45 project outwardly from the sprocket 30; and on each stud 45 is rotatably mounted a pair of planetary gears 46 and 41. The gear couple 46 and 41 is secured together in suitable manner, or the same may be formed integrally. The smaller gear 46 of the couple meshes with the ring gear 44. In the position of the gear 21 shown in Fig. 1', the same meshes with the planetary gear 41, thus establishing a driving connection through epicyclic gearing between the sprocket 25 and the sprocket 30. If the gear 21 be shifted so that the jaws 33 intermesh with the jaws 32, the sprockets 25 and 30 are locked together due to the spline 28. Accordingly, the sprockets 25 and 30 would, in such case, rotate together.

The small gears 46 of the gear couples are always in mesh with the ring gear 44. When the gear 21 is shifted so that the jaws 33 and 32 intermesh, the larger gears 41 .rotate'idly. When the gear 21 is shifted so that the same meshes with the larger gears 41, the smaller gears 46 roll around within the ring gear 44 and drive the sprocket 30. It is thus apparent that I have provided a variable speed-driving means,

since by shifting the gear 21 to one position or the other, either a relatively high speed or a relatively low speed of driving may be effected.

In all of the figures of the drawings, the sprocket chains have been omitted to make the illustration of the invention clearer.

My improved arrangement for driving the rotary table does away with the objectionable length of sprocket chain which it was necessary to use with prior constructions for driving the rotary. The chain, which extends from the change speed driving means in my improved drawworks to the rotary table, is not long enough so that the same is liable to flop or whip. Moreover, the chain extending to the rotary table is low enough so that the drive shaft of the rotary may be set quite close to the floor. The driving shaft of the rotary may be thus placed close to the floor without necessitating driving the same by a chain at an objectionable angle.

In the preferred form of my invention, it is possible to secure variable speeds of the rotary without changing the speed of rotation of the counter-shaft or line shaft. Since a change in speed of the counter-shaft affects other parts of the drawworks, there is considerable advantage in the ability to thus change the speed of the rotary table independently of any change in the speed of rotation of the counter-shaft. Moreover, it is not always convenient to change the speed of the prime mover; and, therefore, the variable speed driving means has the advantage that the rotary table may be driven at different speeds without changing the speed of the prime mover.

While I have illustrated and described one specific form of speed-reduction means interposed between the counter-shaft of a drawworks and the rotary table which is to be driven, it will be understood that the invention is not restricted to the particular construction and arrangement shown, but may be variously modified within the contemplation of the invention and under the scope of the following claims.

I claim:

1. In a drawworks of the two-post type, in combination, a drum shaft, a counter-shaft, a twopost frame for supporting said shafts, said counfer-shaft having a free end projecting, a drum on said drum shaft, and means for establishing a driving connection between the counter-shaft and a rotary table, comprising a driving member rotatably mounted on the projecting end of said countershaft, means for clutching said driving member tosaid counter-shaft, and variable speed driving means for connecting said driving member in operative driving relation with a rotary table.

. 2. In a drawworks of the two-post type, in combination, a drum shaft, a counter-shaft, a two-post frame for supporting said shafts, said counter-shaft having. a free end projecting, a drum on said drum shaft, a sprocket on said pro jecting end of said counter-shaft, and means for establishing a driving connection between the sprocket on the counter-shaft and a rotary table, comprising variable speed driving means. 3. In a drawworks of the type described, in combination, a drum shaft,- a counter-shaft, means for supporting said shafts, adrum on the drum shaft, and means for establishing a driving connection between the counter-shaft and a rotary table, comprising change speed driving means rotatably mounted on the end of the drum shaft, and operative driving connections between said change speed driving means and the countershaft.

4. In a drawworks of the type described, in combination, a drum shaft, a counter-shaft,

means for supporting said shafts, a drum on the drum shaft, and means for establishing a driving connection between the counter-shaft and a rotary table, comprising a pair of coaxial sprockets rotatably mounted on the drum shaft, one of said sprockets being operatively connected with the sprocket on the counter-shaft and the other being provided for establishing a driving connection with the rotary table, and epicyclic gearing for connecting said sprockets so that one is driven by the other at reduced speed.

5. In a two post drawworks, a drum shaft, a counter-shaft, a two post frame for supporting said shaft, said counter-shaft having the free end projecting beyond said frame, a drum on said drum shaft, a pair of sprockets on the projecting end of said drum-shaft, one of said sprockets constituting a driven sprocket and the other a rotary table driving sprocket and variable speed means between said sprockets comprising speed reducing gears and means alternatively to clutch said sprockets together directly or through said gears.

EDGAR E. GREVE. 

